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Full text of "Practical Organic Chemistry"

QUINONK AND OUINOL

The reliction consists in the oxidation and elimination of the amino-
<_n'oup and simultaneous replacement <>f l\vo hydrogen a'tnms in the
hen/ene nucleus hy oxygen, and cannot well he expressed in the
form of equation.

Pro/tM'fies. ~~( .ioklen-vellow, noodle-shaped crystals ; m. p.
Ii6: ; with difficulty soluble in water, readily soluble in alcohol
and ether ; sublimes on heating ; its vapour has a penetrating-
sin ell and attacks the eyes.

Kctii'tioii. ....... Dissolve a few crystals in water and add a solution

of sulphur dioxide. The solution first darkens from the forma-
tion of quinhydrone, C,.I IVO.,. C,.I i. t(()Il ).,, and then becomes
colourless and contains quinol.

Qtlinol. ...... The other half of the product  is treated with a

current of sulphur dioxide until, after standing for a time, it
retains the smell of the gas.* The sulphur dioxide is most
conveniently obtained from a bottle of liquid, or it may be pre-
pared by dropping1 concentrated sulphuric acid from a tap-
funnel on to sodium sulphite. The liquid, after standing one to
two hours, is extracted with ether until no more quinol is
removed. The ether is distilled off, ami the dark coloured
residue rccrystallised from water with the addition of sulphur
dioxide and a little animal charcoal. Yield about 10 grains.

c,;n.,o2 4- sex 4- 2iLo - c.jii.jf

/V<yVr//V,v.~- -Colourless prisms ; m.p. 169' ; sublimes at a
gentle heat ; easily soluble in alcohol, ether, and hot water.

Rent'ti'tws.  i. To a solution of quinol in water, add a few
drops of ferric chloride. The solution turns brown and ether
now extracts quinone.

Ct;H4(On)., 4- 2FeCl;{ - CUH,,(), + 2FeCl, 4- 2HC1.

2. Add to the solution of quinol in water, a drop of copper
sulphate, and caustic soda, and warm. Cuprous oxide is pre-
cipitated.

cfln4(Qii)a 4- 2Cuo = tyi.tO., + Gu-jU + H.A

See Appendix^ p. 297.

ft'lf

COHEN'S ADV. i. o. c.